Hot box detectors



June 25, 1963 'c. A. GALLAGHER ETAL HOT BOX DETECTORS Filed March 16.1959 Tu l- INVENTORS W m 4; N a m G.

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OLE'A/O/D RELAY I I l I 1 l I I l I 1 l I I I I I I I I I 1 L detectiondevice is mounted United States Patent Ofice 3,095,171 Patented June 25,1963 3,095,171 HOT BOX DETECTORS Cornelius A. Gallagher, Hicksville, andWilliam M.

Pelino, Garden City, N.Y., assignors to Serra Corporation of America,New Hyde Park, N.Y., a corporation of New York Filed Mar. 16, 1959, Ser.No. 799,620 1 Claim. (Cl. 246-169) In our copending application, SerialNo. 747,553, filed June 30, 1958, now Patent 2,880,309, slant aspectviewing of journal boxes and wheel-axle junctions was described andclaimed. This application is limited to the vertical-plane aspect ofviewing journal boxes, wheel-axle junctions, or other areas which carryheat information of the journal boxes.

In the slant aspect viewing arrangement, an infra-red alongside a trackrail and projects an image of the heat-responsive means along an axisgenerally inclined to the horizontal plane and longitudinally of thetrack. The image is focussed on a side of a passing journal box.Ordinarily, for iii-directional detection, two infra-red detectors arerequired. ,In addition, a circuit arrangement for selectively gatingonly pertinent heat information to telemetering devices is employed.This circuit rejects influences which are not relevant to adetermination of the journal box heat condition. The gating circuit isgenerally operated by a wheeltrip device of a type which producesanelectrical impulse in response to a wheel rolling thereover,

In the slant aspect arrangement the box, at the instant of viewing, isat a position somewhat removed from the location of the infradeddetector. The wheeltrip device is located for operation by a wheelcorresponding to the journal box to be viewed. Since the axes of viewingare widely divergent for trafiic moving in opposite directions, two setsof wheel-trip devices are required if the same side of the journal boxis to be viewed for either direction.

Experimental studies have shown that the forward side of a movingjournal box trailing side and, further, the temperature differentialbetween the upper and lower portions of the trailing side isconsiderably greater than the corresponding portions of the trailingside. Thus, when viewing the Opposite sides of the box for the differentdirections of traflic, signal analysis is more troublesome because ofthese different temperatures and temperature gradients which exist onthe forward and trailing sides of the box.

. Accordingly, it is a primary object of this invention to provide a hotbox detection system comprising only a single detector for consistentlyviewing the same area indicative of temperature conditions of journalboxes on rolling stock moving in either direction.

It is a further object of the invention to provide a hot box detectionsystem wherein the infrared detector is mounted alongside a track railfor vertical-plane viewing of bidirectional trafiic, and utilizing onlya single wheel-trip device; stated in other words, the wheel-trip meansutilized for gating for one direction of tuafiic flow on a given trackis also used for gating for the opposite direction of trafiic flow onthe same tnack.

In accordance with a feature of the invention, the hea tresponsive meansis coupled to a normally blocked gating circuit which is controlled by aWheel-trip device. The whcel-trip device is mounted alongside a trackrail within an area defined by planes passing through the vertical sidesof the journal box, whereby when the wheeldrip device is operated by awheel passing thercover, the heat indicating area is in position to beobserved by the heatresponsive device, irrespective of the direction inwhich the rolling stock is travelin is generally cooler than the Theabove-mentioned and other features and objects of this invention and themanner of attaining them will be best understood by reference to thefollowing description of an embodiment of the invention taken inconjunction with the accompanying drawing, wherein:

FIGURE 1 is a side view of a length of track including the infra-reddetector, journal box and a portion of rolling stock;

FIGURE 2 is a block diagram of a signalling circuit, including aschematic showing of the detector, for app1ying radiant energy signalsto a telemetering circuit; and

FIGURE 3 is a diagrammatic illustration of a wheeltrip device.

The general orientation of the detector and journal box is illustratedin FIGURE 1. The infra-red detector 1 is mounted alongside a track rail2 supported on railroad ties 3, 4 and is disposed so as to project animage of a heat-sensitive cell along an axis 5 directed generallyvertically upwardly; that is, in the vertical plane which is at a nightangle to the longitudinal direction of the track 2. In the illustratedembodiment, a journal box 6 is viewed by the detector 1. However, it isnow that the best condition of a bearing can be determined by detectingthe heat energy at an adjacent wheel-axle junction. For viewing thewheel-axle junctions, the detector is mounted between the rails, andFIGURE 1 may be construed accordingly with the axis 5 being directed atthe junctions. The journal box 6 is shown as part of the u'uck'strueture7 and is mounted at the end of an axle which supports a pair of wheels,one of which, 8, is shown. A wheel-trip device 9 is shown schematicallyby dotted lines, and in accordance with the invention, is located sothat when the wheel 8 rolls thereover, from either direction, thejournal box 6, or wheel-axle junction, is in a position to be viewedhythe detector 1. That is, the detector and thewheel-trip device arelocated in an area defined by planes passing through the vertical sidesof th journal box 6.

Referring to FIGURE 2, the hot box detector comprises generally a pairof heat-responsive cells, such as thermistor flakes 10, 11, connected ina polarized bridge circuit. One of the cells, for example 10, ispositioned to antercept the incident radiant energy from the journal boxor wheel-axle junction and the other thermistor flake 11 is preferablyshielded, as indicated by dotted lines 12, so as to provide an ambientor reference response against which the transient response of cell 10may be compared.

The cell 10 is imaged on the heat-indicating area (journal box orwheel-axle 'junctionybyophcsincluding a lens 13 and a shutter 14.Usually, the detector 1 is provided in duplicate for any singleinstallation, there being another unit on the opposite side of the othertrack rail to detect simultaneously journal bearing temperatures at bothends of the same axle.

The output from the thermistor bridge is applied to an amplifier 15 andthe amplified signal is applied to a normally blocked gate 16. Incertain installations the signals from amplifier 15 may be applieddirectly to telemetering and alarm circuits 17, where signal analysis isaccomplished. The alarm circuits may be of the audible or visual type.In the preferred circuit the gate 16 is utilized to exclude heat signalsnot directly attributable to the journal box 6.

The gate 16 is unblocked, or opened, by the wheeltrip device 9, showndiagrammatically in FIGURE 3 and described and claimed in detail incopending application Serial No. 627,330, filed December 10, 1956, inthe names of Gallagher et al. Briefly, the preferred wheeltrip device 9comprises a polarized horseshoe-shaped magnet which is so disposed thatthe gap thereof is transiently closed by the flange of the wheel 8. Anenergized winding coupled to the magnet develops a trip signal in theform of an electrical impulse in response to the closing of the gap. Asshown in FIGURE 3, the electromagnetic components are cast in a ruggedplastic housing 20, which is secured to the side of the rail 2,preferably by bolts 21. One pole of the magnet is shown by dotted lines22, and the other pole is in contiguous relation with the underside ofthe head of the rail. Thus, when a wheel passes over the wheel-tripdevice, a magnetic circuit, including the rail head and wheel, is closedand produces a pulse in the energized winding which surrounds a portionof the magnet. The same pulse is produced regardless of the direction oftrain travel, and therefore the wheel-trip may be said to bebi-directionally responsive.

The gate 16 may be in the form of a single relay, which is closed inresponse to the pulse from the wheeltrip device 9. While the relay isclosed, signals corresponding to the amplified signals from amplifier 15are applied to the telemetering circuit 17. Alternatively, the gate 16may be a multivibrator triggered into a first state of operation by thewheel-trip pulse and the output thereof being amplitude-modulated by theradiant energy signals from the amplifier 15.

In the illustration of FIGURE 1, the wheel-trip device 9 is shownlocated on the optic axis 5. If the magnetic gap is located on thisaxis, then one-half of the bottom of the box will be viewed by thedetector. For example, if the journal box is moving from left to rightin the sense of the drawing, the wheel-trip is operated approximatelywhen the center of the journal box is aligned with the axis 5, as shown.The gate is then opened and remains open for a time sufiicient to permitthe detector to view a part, or all, of the bottom of the journal boxsurrounding the axis 5 and between lines 18 and 19.

'In order to maintain the gate 16 in the open condition for a sufiicienttime for the thermistor flake to be activated by the radiations from thejournal box, the wheel-trip preferably includes a storage circuit, asfor example a monostable multivibrator or a time delay dropout relay.The trip signal is pre-set to have a duration long enough to allow cellresponse along half of the bottom of the journal box 6 for a trainmoving at maximum speed, whereby for trains moving at slower speeds asmaller area is viewed.

In order to protect the internal parts of the housing 1 during periodswhen no trains are passing, shutter means 14 are operated to close andopen a viewing aperture in the housing 1. The shutter means 14 remainsopen as long as a train is passing the detector. The wheel-trip 9 inconjunction with a relatively long time-constant storage circuit 23provides the actuating signal for a shutteropening solenoid 24. Thus, ifthe time constant provided by the storage means 23 is long enough tomaintain a shutter-opening signal of the solenoid 24 for the slowerspeedtrains, as for example down to five miles an hour, the shutter 14 willalso remain open for all greater train speeds. When the train passescompletely, the storage device 23 will fail to excite solenoid 24 andthe shutter means 14 will close, as by spring or gravity-operated means,to await the next train.

It should now be apparent that by the unique orientation of the detectorand wheel-trip device, it is possible to monitor the journal boxradiations from rolling stock moving in either direction, using only asingle detector and wheel-trip device. The invention, therefore, reducesthe required number of detectors and wheel-trip devices by half.

While the foregoing description sets forth the principles of theinvention in connection with specific apparatus, it is to be clearlyunderstood that this description is made only by way of example and notas a limitation of the scope of the invention as set forth in theobjects thereof and in the accompanying claim.

We claim:

A hot-box detector, comprising an infrared detection device mountedalongside a longitudinally extending length of railroad track, saiddevice comprising heatresponsive means producing an electrical signal inresponse to incident radiant energy, optical means imaging saidheat-responsive means along an axis directed upwardly in a verticalplane that is at a right angle to the longitudinal direction of thetrack and in a direction to view on passing journal boxes or axles anarea indicative of heat in an adjacent journal bearing, a normallyblocked gating circuit coupled to the output of said heat-responsivemeans, radiant-energy indicating means coupled to the output of saidgating circuit, actuating means for said gating circuit includingbi-directionally responsive wheel-operated trip means symmetricallydisposed on opposite sides of said vertical plane and producing anelectrical impulse for each passing wheel, the connection to said gatingcircuit being such as to open the same in response to said electricalimpulse, whereby signals from said heat-responsive device are passed tosaid radiant-energy indicating means regardless of the direction oftrain movement on said length of track.

References Cited in the tile of this patent UNITED STATES PATENTS2,818,508 Johanson et al. Dec. 31, 1957 2,856,540 Warshaw Oct. 14, 19582,892,078 Orthuber June 23, 1959 FOREIGN PATENTS 940,785 Germany Mar.29, 1956 1,005,876 Germany Apr. 4, 1957 112,527 Switzerland Nov. 2, 1925

